The business case for the Superchargers is currently one of added value for Model S sales.

Tesla owners aren't charged a penny to use the chargers, and that's likely to remain the case for the foreseeable future.

As a Model S buyer, it's nice to know you'll eventually be able to travel the country without spending a dime on fuel.

But Tesla's Supercharger technology is among the best fast-charging tech out there, and stations that can replenish 200 miles of battery capacity in 20 minutes have plenty of potential outside Tesla's realm.

What if, asks The Wall Street Journal, Tesla Motors could expand its network faster than anyone else? And what if other cars were eventually able to use that network?

The paper likens the move to the first network of filling stations across the U.S. These were controlled by--get this--Henry Ford, shortly after the Model T was launched.

It's great having people fill their Model S for free at those Superchargers, but even if Tesla's success continues, it will only ever be one maker of electric cars.

There are thousands of other electric vehicles out there with charging requirements, and allowing them access to the national Supercharger network could be a real money-spinner.

Charging: In Tesla's best interests

Tesla is also perfectly placed to control such a network.

Many companies have a passing interest in running an electric network--automakers, utility operators, gas stations--but all have other interests at heart. Tesla's business is only in electric vehicles, so there's all the more to be gained from investing in the technology.

And while there are several competing charging technologies, such as the CHAdeMO standard adopted by many Japanese automakers, Tesla could potentially share its tech with some big automakers like Toyota and Daimler--both of whom have technology deals with Tesla.

Tesla has an exciting product line ahead of it, but The Wall Street Journal sums up the charging situation quite nicely:

"It has proven much more profitable to be Chevron than it is to be GM."

It will of course be hugely expensive to set up a wide-reaching Supercharger network, as investment site Seeking Alpha points out (each station costs around $300K)--but that's all the more reason to expand the network beyond merely free Tesla charging.

A Model S in every garage would be nice for Tesla Motors, but every electric car in the land using their chargers could be even better...